Method of controlling weeds in a cultivation area of determinate soybean

ABSTRACT

The present invention can provide a method having superior crop selectivity for weed control in a cultivation area of determinate soybean. The method includes a step of applying trifludimoxazin in a cultivation area of determinate soybean.

TECHNICAL FIELD

This application claims priority to and the benefit of Japanese PatentApplication No. 2019-073974 filed on Apr. 9, 2019 and U.S. patentapplication Ser. No. 16/391,919 filed on Apr. 23, 2019, the entirecontents of which are incorporated herein by reference.

The present invention relates to a method of controlling weeds in acultivation area of determinate soybean.

BACKGROUND ART

Hitherto, a method of treating trifludimoxazin has been known, as amethod for controlling weeds in a cultivation area of soybean (seePatent Literature 1). Also, several types of soybean such as determinatesoybean, indeterminate soybean and semi-determinate soybean are known(see Non Patent Literature 1). However, it is not known that weeds canbe controlled with particularly superior crop selectivity by applyingtrifludimoxazin in a cultivation area of determinate soybean.

CITATION LIST Patent Literature

-   PTL 1: WO 2010/145992 pamphlet

Non Patent Literature

-   NPL 1: Crop Science 12 (1972), 235-239.

SUMMARY OF INVENTION Technical Problem

An object of the present invention is to provide a method havingsuperior crop selectivity for weed control in a cultivation area ofdeterminate soybean.

Solution to Problem

The present inventor has found out that weeds can be effectivelycontrolled with superior crop selectivity by applying trifludimoxazin ina cultivation area of determinate soybean.

The present invention includes the following aspects [1] and [2].

[1] A method of controlling weeds in a cultivation area of determinatesoybean, the method including a step of applying trifludimoxazin in thecultivation area of determinate soybean.

[2] The method according to [1], wherein trifludimoxazin is applied to asoil of the cultivation area of determinate soybean.

Advantageous Effects of Invention

Weeds can be controlled in a cultivation area of determinate soybeanwithout causing significant injury on determinate soybean according tothe present invention.

DESCRIPTION OF EMBODIMENTS

The method of controlling weeds in a cultivation area of determinatesoybean of the present invention (hereinafter, sometimes referred to as“present method” or “method of the present invention”) includes a stepof applying trifludimoxazin in a cultivation area of determinatesoybean.

Trifludimoxazin is a compound showing herbicidal activity by inhibitingprotoporphyrinogen oxidase that is involved in chlorophyll biosynthesissystem, and can be manufactured by a known method.

Soybean in the present invention is a plant species generally describedas Glycine max, but it also includes ‘biologically identical specieshaving the homogeneous genome to Glycine max’ such as wild soybean(Glycine soja, also known as Glycine max subsp. soja). Determinatesoybean in the present method is a variety group among theaforementioned soybean showing a genotype dt1/dt1 at the locus (Dt1)relating to the growth habit. Varieties showing Dt1/dt1 or Dt1/Dt1 onthe locus become indeterminate soybean or semi-determinate soybeandepending on the condition on another locus (Dt2) relating to the growthhabit.

In the present method, variations within determinate soybean are notparticularly limited as long as the determinate soybean is a varietywhich is usually cultivated. For examples, determinate soybean belongingto diverse maturity groups from early-maturing to late-maturing can beused. Also, the varieties are not limited by diverse intended usages ofthe harvest of determinate soybean. For example, determinate soybean forany of the intended usages such as seed production, ornamentals, greenmanures, silage, grains, and the like can be used. For grains,determinate soybean for any of the intended usages such as food, oilextraction, feed, flour milling, and the like can be used.

Examples of determinate soybean varieties include Toyomusume,Sachiyutaka, Fukunari, Tambaguro, Enrei, Hobbit87, Asgrow AG53X6,Credenz CZ5225LL and the like. Examples of soybean which does not belongto determinate soybean includes Williams 82, Harosoy, Kurosengoku,Tsurusengoku, wild soybean, Asgrow AG4934, Credenz CZ4590RY and thelike. Although the weight of seeds of determinate soybean which can beused in the present method is not particularly limited, a seed weight ofdeterminate soybean is usually within a range of 20 to 600 mg/seed, morepreferably 250 to 500 mg/seed.

The determinate soybean may be the one producible by natural crossing,plants producible by a mutation, F1 hybrid plants, or transgenic plants(also called genetically modified plants). These plants generally havecharacteristics such as tolerance to herbicides, accumulation ofsubstances harmful to insect pests, reduction in sensitivity todiseases, increase in yield potential, improvement in resistance tobiotic or abiotic stress factors, accumulation of substances, andimprovement in preservability and processability.

The F1 hybrid plants are those which are each a first filial hybridobtained by crossing two different varieties with each other and usuallyhave characteristics of heterosis, which is a nature of having moreexcellent trait than both of the parents. The transgenic plants arethose which are obtained by introducing an exogeneous gene from otherorganisms such as microorganisms and have characteristics like thosethat cannot be easily obtained by crossbreeding, mutation induction, ornatural recombination in natural environments.

Examples of the technologies used to create the above plants includeconventional type variety improvement technologies; geneticrecombination technologies; genome breeding technologies; new breedingtechnologies; and genome editing technologies. The conventional typevariety improvement technologies are specifically technologies forobtaining plants having desired properties by a mutation and crossing.The genetic recombination technologies are technologies in which atarget gene (DNA) is extracted from a certain organism (for example,microorganism) to introduce it into a genome of a different targetorganism, thereby imparting new properties to the organism, andantisense technologies or RNA interference technologies for impartingnew or improved characteristics by silencing a certain genes existing inplants. The genome breeding technologies are those improving breedingefficiency by using genome information and include DNA marker (alsocalled genome markers or genetical markers) breeding technologies andgenomic selection. For example, the DNA marker breeding is a method inwhich a progeny having a target gene with a useful trait is selectedfrom a lot of cross progenies by using a DNA marker which is a DNAsequence and is a marker of the presence position of a gene with aspecific useful trait on a genome. This method has the characteristicsthat the time required for breeding can be efficiently reduced byanalyzing the cross progeny using a DNA marker when the progeny is ajuvenile plant.

Also, the genomic selection is a technique in which a prediction formulais created from a phenotype obtained in advance and genome informationto predict the characteristics from the prediction formula and thegenome information without any evaluation of the phenotype and istechnologies contributing to improvement in efficient breeding. The newbreeding techniques are a generic term of variety-improvement(=breeding) techniques that are combinations of molecular biologicaltechniques. Examples of the new breeding techniques includecisgenesis/intragenesis, introduction of an oligonucleotide-directedmutation, RNA-dependent DNA methylation, grafting onto a GM rootstock orscion, reverse breeding, agroinfiltration, and seed productiontechnology (SPT). The genome editing technologies are those in whichgenetic information is transformed in a sequence-specific manner whichenables, for example, deletion of a base sequence, substitution of anamino acid sequence, and introduction of an exogenous gene. Examples oftools for these techniques include sequence-specific genome modificationtechniques such as zinc-finger nuclease (ZFN), TALEN, CRISPR/Cas9,CRISPER/Cpfl, and Meganuclease which each enable sequence-specific DNAscission and CAS9 Nickase and TargetAID which are each created bymodifying the aforementioned tools.

Examples of the plants mentioned above include plants listed in GMAPPROVAL DATABASE of genetically modified crops in the electronicinformation site (http://www.isaaa.org/) of INTERNATIONAL SERVICE forthe ACQUISITION of AGRI-BIOTECH APPLICATIONS (ISAAA). More specifically,these examples include herbicide tolerant plants, insect pest resistantplants, disease resistant plants, and quality modified (for example,increase or decrease in content of a certain component or change incomposition) plants of products (for example, starch, amino acid, andfatty acid), fertile trait modified plants, abiotic stress tolerantplants, or plants modified in traits relating to growth and yield.

Examples of plants to which tolerance to herbicides is imparted aregiven as follows.

The tolerance to herbicides is obtained, for example, by reducing thecompatibility of a chemical with its target, by rapid metabolism (forexample, breakdown or modification) resulting from the expression of achemical deactivation enzyme, or by inhibiting the incorporation of achemical into a plant body or the transfer of the chemical in the plantbody.

The plants to which herbicide tolerance is imparted by geneticrecombination technologies include plants to which tolerances to thefollowing inhibitors are imparted by genetic recombination technologies:4-hydroxyphenyl pyruvate dioxygenase (hereinafter abbreviated as HPPD)inhibitors such as isoxaflutole and mesotrione, acetolactate synthetase(hereinafter abbreviated as ALS) inhibitors such as imidazolinone typeherbicides including imazethapyr and sulfonylurea type herbicidesincluding thifensulfuron-methyl, 5-enolpyruvylshikimate-3-phosphatesynthase (hereinafter abbreviated as EPSP) inhibitors such asglyphosate, glutamine synthetase inhibitors such as glufosinate, auxintype herbicides such as 2,4-D and dicamba, oxynil type herbicidesincluding bromoxynil, and protoporphyrinogen oxidase (herein afterabbreviated as PPO) such as flumioxazin.

In the present method, trifludimoxazin is usually used after makingformulation by mixing with a carrier such as a solid or liquid carrier,and adding auxiliary agents for formulation such as a surfactant asnecessary. In the case of making formulation, preferable formulationtype is a soluble liquid, soluble granule, an aqueous suspensionconcentrate, oil-based liquid suspension, wettable powder, waterdispersible granule, granule, aqueous emulsion, oil-based emulsion, andemulsifiable concentrate. More preferable formulation type is aqueoussuspension concentrate. Moreover, a formulation containingtrifludimoxazin singly as an active ingredient may be independently usedor may be tank-mixed with a formulation containing other herbicide asactive ingredients. Also, a formulation containing trifludimoxazin andother herbicide may be used. Also, a formulation containingtrifludimoxazin and other herbicide as active ingredients may betank-mixed with a formulation containing, as active ingredients,herbicides different from the above herbicides. The content of theactive ingredients (trifludimoxazin or a total of trifludimoxazin andother herbicides) in the formulation is usually within a range of 0.01to 90% by weight, preferably 1 to 80% by weight.

In the present invention, “a cultivation area of determinate soybean”includes the area where determinate soybean is growing or will grow.

In the present method, “applying trifludimoxazin in a cultivation areaof determinate soybean” includes applying trifludimoxazin to weedsgrowing in the cultivation area of determinate soybean and applyingtrifludimoxazin to a soil of the cultivation area of determinatesoybean, and is usually conducted using a spray dilution produced bymixing a formulation containing trifludimoxazin with water. The amountof the dilution to be sprayed is usually 10 to 1000 L, preferably 100 to500 L, and more preferably 140 to 300 L per hectare of cultivation areaof determinate soybean though no particular limitation is imposed on it.

In the present method, the application rate of trifludimoxazin ispreferably 5 to 100 g, more preferably 10 to 50 g, still more preferably25 g per hectare of the cultivation area. Examples of the specificapplication rates include 7 g, 8 g, 12 g, 15 g, 18 g, 20 g, 30 g, 40 g,60 g and 80 g per hectare. These application rates can be described with“approximately.” “Approximately” means plus/minus 10%, so, for example,“approximately 10 g per hectare” means “9 to 11 g per hectare.”

Although a period of time for conducting the present method is notparticularly limited, the period of time is usually within a range from5 a.m. to 9 p.m., and the photon flux density at land surface of theplace where the present method is conducted is usually 10 to 2500μmol/m²/s.

The spray pressure when conducting the present method is usually 30 to120 PSI and preferably 40 to 80 PSI though no particular limitation isimposed on it. Here, the spray pressure is a set value just before thedilution is introduced into the nozzle.

The nozzle used in the present method may be flat-fan nozzles ordrift-reducing nozzles. Examples of flat-fan nozzles include Teejet110series and XR Teejet110 series manufactured by Teejet Company. Whenusing these nozzles, the spray pressure is generally 30 to 120 PSI andthe volume median diameter of liquid droplets discharged from the nozzleis usually less than 430 micro meter. The drift-reducing nozzle is anozzle which leads to less drift compared with a flat-fan nozzle andwhich is called an air induction nozzle or pre-orifice nozzle. Thevolume median diameter of a liquid droplet discharged from thedrift-reducing nozzle is usually 430 micro meter or more.

In the present method, seeds of determinate soybean are seeded to thecultivation area by usual methods. The present method may be conductedbefore seeding and may be conducted concurrently with and/or afterseeding. Namely, examples of the number of times that the present methodis conducted include 1 to 3 times during the cultivation of determinatesoybean. In the case of once, the present method may be conducted oncebefore, concurrently with, or after seeding. In the case of twice, thepresent method may be conducted twice except before seeding, twiceexcept concurrently with seeding, or twice except after seeding. In thecase of three times, the present method may be conducted three timesbefore, concurrently with, and after seeding.

When the present method is conducted before seeding, the present methodis conducted usually from 50 days before seeding to immediately beforeseeding, preferably from 30 days before seeding to immediately beforeseeding, more preferably from 20 days before seeding to immediatelybefore seeding, still preferably from 10 days before seeding toimmediately before seeding.

When the present method is conducted after seeding, the present methodis conducted usually from immediately after seeding to before flowering,preferably from immediately after seeding to before emergence, and 1 to6 true leaf stage of determinate soybean.

The case where the present method is conducted concurrently with seedingis a case where a sowing machine and a spraying machine are integratedwith each other.

In the present method, seeds of determinate soybean may be treated withone or more compounds selected from the group consisting of insecticidalcompounds, nematicidal compounds, fungicidal compounds, and plant growthregulators. Examples of compounds to be used for the seed treatmentinclude neonicotinoid compounds, diamide compounds, carbamate compounds,organophosphorous compounds, biological nematicidal compounds, otherinsecticidal compounds and nematicidal compounds, azole compounds,strobilurin compounds, metalaxyl compounds, SDHI compounds, otherfungicidal compounds, and plant growth regulators.

Target weed species controlled in the present method include thefollowings as examples, however they are not limited thereto.

Broadleaf weeds: Lambsquarters (Chenopodium album), Kochia (Kochiascoparia), Redroot pigweed (Amaranthus retroflexus), smooth pigweed(Amaranthus hybridus), Palmer amaranth (Amaranthus palmeri), Waterhemp(Amaranthus tuberculatus=Amaranthus rudis=Amaranthus tamariscinus),Amaranthus quitensis, Wild poinsettia (Euphorbia heterophylla), hairyfleabane (Conyza bonariensis), Conyza sumatrensis, marestail (ConyzaCanadensis), common ragweed (Ambrosia artemisiifolia), and giant ragweed(Ambrosia trifida).

Grass weeds (Poaceae): barnyardgrass (Echinochloa crus-galli),junglerice (Echinochloa colona), green foxtail (Setaria viridis), giantfoxtail (Setaria faberi), large crabgrass (Digitaria sanguinalis),Jamaican crabgrass (Digitaria horizontalis), Digitaria insularis,Goosegrass (Eleusine indica), Johnsongrass (Sorghum halepense), Italianryegrass (Lolium multiflorum), perennial ryegrass (Lolium perenne), andrigid ryegrass (Lolium rigidum).

In the present method, trifludimoxazin may be used in combination withone or more other herbicides. For here, using in combination includestank-mix, pre-mix, and sequential treatment. In the case of sequentialtreatment, the order of treatments is not particularly limited.

Herbicides which may be used in combination with trifludimoxazin ispreferably one or more of glyphosate-potassium,glyphosate-dimethylamine, glyphosate-monoethanolamine,glyphosate-isopropylammonium, pyroxasulfone, mesotrione, isoxaflutole,metribuzine, dicamba-diglycolamine, dicamba-biproamine,dicambatetrabutylammonium, dicamba-tetrabutlyphosphonium,glufosinate-ammonium, imazethapyr-ammonium, dimethenamid-P,pendimethalin, and saflufenacil, and more preferably, saflufenacil.

When aforementioned herbicide is used in combination withtrifludimoxazin, the weight ratio of trifludimoxazin to other herbicideis usually within a range of 1:0.1 to 1:500, preferably 1:0.5 to 1:100,and more preferably 1:1 to 1:10. Examples of the specific weight ratiosinclude 1:0.2, 1:0.4, 1:0.6, 1:0.8, 1:1.5, 1:2, 1:2.5, 1:3, 1:4, 1:7,1:15, 1:20, 1:25, 1:30, 1:40, 1:50, 1:80, 1:150, 1:200, 1:250, 1:300 and1:400. These weight ratios may be described with approximately.Approximately means plus/minus 10%, so, for example, “approximately 1:2”means 1:1.8 to 1:2.2.

The cultivation of determinate soybean in the present invention can bemanaged according to the plant-nutrition in the common crop cultivation.The fertilization system may be based on Precision Agriculture adoptingvariable rate application or may be conventionally uniform one. Inaddition, nitrogen fixation bacteria and mycorrhizal fungi may beinoculated by seed treatment.

EXAMPLES

The present invention will be explained by way of examples, but thepresent invention should not be limited thereto.

First, evaluation criteria for a herbicidal effect, and crop injurydescribed in the following examples are shown.

(Herbicidal Effect and Crop Injury)

The evaluation of the herbicidal effect and crop injury is classifiedinto 0 to 100, where the numeral “0” indicates no or little differencein the state of germination or growth of weeds or soybean under test atthe time of examination as comparison with untreated weeds or soybean,respectively and the numeral “100” indicates the complete death of weedsor soybean under test or the complete inhibition of their germination orgrowth of weeds or soybean under test.

Example 1

A pot is filled with a soil, and the determinate soybean, indeterminatesoybean, semi-determinate soybean, palmer amaranth, waterhemp, kochia,common ragweed and marestail are sown thereto. Two days later,trifludimoxazin spray liquid (prepared by diluting trifludimoxazinformulation (an aqueous suspension concentrate containing 500 g/L oftrifludimoxazin) with water) is uniformly applied onto the pot using asprayer at the amount of 200 L per hectare so that the application rateof trifludimoxazin may be 25 or 50 g per hectare. 21 days after thetreatment, herbicidal effects and injuries on various soybeans areinvestigated. High herbicidal effects on all weeds are confirmed. It isalso confirmed that injury on determinate soybean is less than those onindeterminate soybean and semi-determinate soybean.

Example 2

A pot is filled with a soil, and then Palmer amaranth, waterhemp,kochia, common ragweed and marestail are sown thereto. On the same day,trifludimoxazin spray liquid (prepared by diluting trifludimoxazinformulation (an aqueous suspension concentrate containing 500 g/L oftrifludimoxazin) with water) is uniformly applied onto the pot using asprayer at the amount of 200 L per hectare so that the application rateof trifludimoxazin may be 25 or 50 g per hectare. On the next day,determinate soybean, indeterminate soybean, and semi-determinate soybeanare sown. 21 days after sowing soybeans, herbicidal effects and injurieson various soybeans are investigated. High effects on all weeds areconfirmed. It is also confirmed that injury on determinate soybean isless than those on indeterminate soybean and semi-determinate soybean.

Example 3

Four varieties of determinate soybean, four varieties of indeterminatesoybean, Palmer amaranth, kochia and large crabgrass were sown to a potfilled with a soil. On the next day, a trifludimoxazin spray liquid(prepared by diluting an emulsifiable concentrate of trifludimoxazinwith water) was uniformly sprayed onto the pot at the amount of 200 Lper hectare so that the application rate of trifludimoxazin might be 25or 50 g per hectare. 18 days after treatment, herbicidal effects onweeds and injury on soybeans were investigated. As a result, theherbicidal effect on each of the three weeds was 100. The results ofevaluation of injury on soybeans are shown in Table 1.

TABLE 1 Variety/growth habit 25 g/hectare 50 g/hectareTambaguro/Determinate 0 10 Toyomusume/Determinate 0 5Sachiyutaka/Determinate 0 0 Fukunari/Determinate 0 0Kurosengoku/Indeterminate 30 60 Wild soybean/Indeterminate 100 100Williams 82/Indeterminate 40 80 Harosoy/Indeterminate 30 50

INDUSTRIAL APPLICABILITY

Weeds can be controlled in a cultivation area of determinate soybeanwith superior crop selectivity according to the present invention.

1. A method of controlling weeds in a cultivation area of determinatesoybean, the method comprising a step of applying trifludimoxazin in thecultivation area of determinate soybean.
 2. The method according toclaim 1, wherein trifludimoxazin is applied to a soil of the cultivationarea of determinate soybean.